D rechargeable battery packs are composed of several D-size batteries (a standard size) arranged in combination, either in parallel or in series. They provide a level of power that is a multiple (or close to one) of the power provided by the individual cells.
What are D rechargeable battery packs used for?
D cells are typically used in high-drain applications, that is, in devices or situations that require consistently high levels of power or a particularly extended running time. This could include products such as large torches, radio receivers and transmitters, electric motors, emergency lighting, safety systems and megaphones. The fact that these battery packs can be recharged makes them well suited for devices that are used on a regular basis.
Added capacity
The large size of D batteries, particularly in combination as in a battery pack, allows them to supply power for a longer time than C, AA or AAA cells would be able to at equal current levels.